1. Technical Field
The present invention relates to a twin-roll type continuous casting machine for producing a metal sheet through the gap between a pair of rolls with a pool of a molten metal being formed on the upper side of the gap between the rolls, and more particularly to a twin-roll type continuous casting machine having an improved construction for pressurizing the melt surface of the melt pool with a gas.
2. Background Art
In recent years research and development has resulted in a twin-roll type continuous casting machine in which a molten metal (hereinafter referred to as "melt") is supplied to the upper side of the gap between a pair of rotating rolls to form a melt pool, and a gas pressure is applied to the melt surface of the melt pool to continuously produce a metal sheet directly through the gap between the rolls.
In connection with such twin-roll type continuous casting machines, it is known that when the melt is brought into contact with the pair of cooled rolls in a pressurized state, it is possible to solidify the melt in a condition of a high rate of heat transfer, thereby enhancing the qualities and flatness of the metal sheet thus cast, and to increase the thickness of the sheet.
In view of the above, there has been proposed, as disclosed in Japanese Pat. Application No. 59-137162 (1984), a continuous casting machine which comprises, as shown in FIG. 4 of the present drawings, a pressurizing chamber 11 formed so as to entirely surround a tundish 5 on the upper side of the rolls 1.
In the above-mentioned continuous casting machine, however, the construction, in which the pressurizing chamber 11 surrounds the tundish 5 entirely for momentarily reserving the melt to be supplied to the gap between the rolls 1, makes it impossible to appropriately supply the melt into the tundish 5 by a ladle (not shown). It is therefore necessary to provide a melting furnace 50 in the pressurizing chamber 11 in order to supply an adequate melt 3 into the tundish 5, and hence the pressurizing chamber 11 is necessarily large. In addition, the presence of the tundish 5 in the pressurizing chamber 11 renders the maintenance of the tundish 5 difficult. Meantime, in FIG. 4, numeral 51 denotes a melt outlet port of the melting furnace 50, and numeral 52 denotes a valve for opening/closing the melt outlet port 51.